Thin-section and isotope data from the Lakadong Limestone, NE India (eastern Tethys)

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Main Authors: Sarkar, Suman, Cotton, Laura, Valdes, Paul J, Schmidt, Daniela N
Format: Dataset Open Access
Language:en
Published: PANGAEA 2022
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author Sarkar, Suman
Cotton, Laura
Valdes, Paul J
Schmidt, Daniela N
author_facet Sarkar, Suman
Cotton, Laura
Valdes, Paul J
Schmidt, Daniela N
collection Datos científicos de ciencias marinas y ambientales
contents The Paleocene Eocene Thermal Maximum (PETM) is associated with major extinction events in the deep ocean, and significant paleogeographic and ecological changes in surface ocean and terrestrial environments. However, the impact of the associated environmental change on shelf biota is less well understood. Here we present a new PETM record of a low paleolatitude late Paleocene-earliest Eocene shallow-marine carbonate platform from Meghalaya, NE India (eastern Tethys). The biotic assemblage was distinctly different to other Tethyan PETM records dominated by larger benthic foraminifera and calcareous algae both in the Paleocene and Eocene. The record is lacking the ecological change from corals to larger foraminiferal assemblages and the Lockhartia dominance, characteristic of other sections in the Tethys. Limestone samples were collected at very high resolution of up to 10 cm from the carbonate successions outcropping in the Mawmluh Cement quarry (25°15.707' N; 91°42.626' E), East Khasi Hills, Meghalaya, NE India. Petrographic thin-sections were prepared from the limestone samples for the light and scanning electron microscopic analysis of the biotic components. In addition to LBF biostratigraphy, carbon isotope analysis was carried out for correlating the shallow benthic zones with the carbon isotope excursion (CIE) for developing a polished record of the PETM. An CIE of ~-3‰ (from 1.96 to -1.08 ‰) tied into the biostratigraphy places the PETM towards the upper part of the Lakadong Limestone from 25.0 to 30.5 m. A change in taxa and forms indicating deeper waters with a concurrent decrease in abundance of shallow water algae suggested a sea-level rise during the onset of the PETM. Oxygen isotope analysis indicated signs of diagenetic overprint in the studied succession.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_942986
institution PANGAEA
language en
publishDate 2022
publisher PANGAEA
record_format pangaea
spellingShingle Thin-section and isotope data from the Lakadong Limestone, NE India (eastern Tethys)
Sarkar, Suman
Cotton, Laura
Valdes, Paul J
Schmidt, Daniela N
Benthic foraminifera; coralline algae; isotope data; Paleocene-Eocene Thermal Maximum; thin-section
The Paleocene Eocene Thermal Maximum (PETM) is associated with major extinction events in the deep ocean, and significant paleogeographic and ecological changes in surface ocean and terrestrial environments. However, the impact of the associated environmental change on shelf biota is less well understood. Here we present a new PETM record of a low paleolatitude late Paleocene-earliest Eocene shallow-marine carbonate platform from Meghalaya, NE India (eastern Tethys). The biotic assemblage was distinctly different to other Tethyan PETM records dominated by larger benthic foraminifera and calcareous algae both in the Paleocene and Eocene. The record is lacking the ecological change from corals to larger foraminiferal assemblages and the Lockhartia dominance, characteristic of other sections in the Tethys. Limestone samples were collected at very high resolution of up to 10 cm from the carbonate successions outcropping in the Mawmluh Cement quarry (25°15.707' N; 91°42.626' E), East Khasi Hills, Meghalaya, NE India. Petrographic thin-sections were prepared from the limestone samples for the light and scanning electron microscopic analysis of the biotic components. In addition to LBF biostratigraphy, carbon isotope analysis was carried out for correlating the shallow benthic zones with the carbon isotope excursion (CIE) for developing a polished record of the PETM. An CIE of ~-3‰ (from 1.96 to -1.08 ‰) tied into the biostratigraphy places the PETM towards the upper part of the Lakadong Limestone from 25.0 to 30.5 m. A change in taxa and forms indicating deeper waters with a concurrent decrease in abundance of shallow water algae suggested a sea-level rise during the onset of the PETM. Oxygen isotope analysis indicated signs of diagenetic overprint in the studied succession.
title Thin-section and isotope data from the Lakadong Limestone, NE India (eastern Tethys)
topic Benthic foraminifera; coralline algae; isotope data; Paleocene-Eocene Thermal Maximum; thin-section
url https://doi.org/10.1594/PANGAEA.942986